Hydrangea plant named &#39;Horwack&#39;

ABSTRACT

A new cultivar of  Hydrangea macrophylla  named ‘HORWACK’ that is characterized by its mophead type inflorescences with showy fertile flowers and smaller less numerous non-showy fertile flowers. its showy flowers that are bicolor with bright green and deep pink sepals, its remontant blooming habit, blooming in mid summer and repeat blooming in fall, its remontant blooming habit, its act plant habit with good branching, and its good disease resistance to powdery mildew and botrytis.

GENUS/SPECIES

Hydrangea macrophylla

VARIETAL DENOMINATION

‘HORWACK’

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar ofHydrangea macrophylla and will be referred to hereafter by its cultivarname, ‘HORWACK’. ‘HORWACK’ represents a new big leaf hydrangea, aperennial shrub grown for landscape use.

‘HORWACK’ arose from an ongoing breeding program by the Inventor withobjectives of developing new cultivars of Hydrangea with improveddisease resistance, good branching, with induction of primarily sterileflowers.

‘HORWACK’ originated from a cross conducted in the Inventor's trialgarden in April of 2004 in Dresden, Germany between the cultivar ‘GreenShadow’ as the female parent and an unnamed plant of Hydrangeamacrophylla from the Inventor's breeding program, designated as cloneno. 59-96/1. The new Hydrangea was selected as a unique single plantfrom the progeny of the above cross in April of 2006.

Asexual propagation of the new cultivar was first accomplished bysoftwood stem cuttings in Dresden, Germany in June of 2006 by theInventor. Asexual propagation by softwood stem cuttings has determinedthat the characteristics of the new cultivar are stable and arereproduced true to type in successive generations.

SUMMARY OF THE INVENTION

The following traits have been repeatedly observed and represent thecharacteristics of the new cultivar. These attributes in combinationdistinguish ‘HORWACK’ as a unique cultivar of Hydrangea macrophylla.

1. ‘HORWACK’ exhibits showy flowers that are bicolor with bright greenand deep pink sepals.

2. ‘HORWACK’ exhibits mophead type inflorescences with showy flowers andsmaller less numerous non-showy fertile flowers.

3. ‘HORWACK’ exhibits a remontant blooming habit, blooming in mid summerand repeat blooming in fall.

4. ‘HORWACK’ exhibits a compact plant habit with good branching.

5. ‘HORWACK’ exhibits dark green-foliage.

6. ‘HORWACK’ has shown resistance to powdery mildew and botrytis.

‘GREEN SHADOW’, the female parent of ‘HORWACK’, differs from ‘HORWACK’in having showy flowers that are bigger, less numerous, and less brightin coloration and in having less resistance to botrytis. The maleparent, clone no. 59-96/1, differs from ‘HORWACK’ in having showyflowers that are dark pink without any green coloration and in having amore vigorous growth habit. ‘HORWACK’ can also be most closely comparedto the cultivars; ‘Kolmagics’ (not patented) and ‘HORGEW’ (notpatented). Both are similar in having bicolor showy flowers that arepink and green. ‘Kolmagics’ differs from ‘HORWACK’ in havinginflorescences that are more ball-shaped and in having showy flowersepals that are more rounded in shape. ‘HORGEW’ differs from ‘HORWACK’in having showy flower color that is less brilliant and distinct, inhaving poorer branching, and in having leaves that are lighter green incolor.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying colored photograph illustrates the overall appearanceand distinct characteristics of the new Hydrangea. The plant in thephotograph is about one-year-old in age as grown in a greenhouse in a1-liter container in Dresden, Germany. The photograph in FIG. 1 providesa view of ‘HORWACK’ in bloom. The colors in the photographs are as closeas possible with the digital photography and printing techniquesutilized and the color codes in the detailed botanical descriptionaccurately describe the new Hydrangea.

BOTANICAL DESCRIPTION OF THE PLANT

The following is a detailed description of one year-old plants of‘HORWACK’ as grown under greenhouse conditions in one-gallon containersin Abbotsford, B.C., Canada. The phenotype of the new cultivar may varywith variations in environmental, climatic, and cultural conditions, asit has not been tested under all possible environmental conditions. Thecolor determination is in accordance with the 2007 R.H.S. Colour Chartof the Royal Horticultural Society, London, England, except wheregeneral color terms of ordinary dictionary significance are used.

-   General description:    -   -   Blooming period.—Remontant, mid-summer and repeats in fall            in-temperate climates in the U.S.        -   Plant habit.—Compact and mounded.        -   Height and spread.—Reaches about 30 cm in height and 45 cm            in width in a one-liter container.        -   Hardiness.—At least in U.S.D A. Zones 5 to 9.        -   Diseases resistance.—Has shown good resistance to powdery            mildew and botrytis.        -   Propagation.—Softwood stem cuttings.        -   Growth rate and vigor.—Moderate.-   Stem description:    -   -   Stem shape.—Round.        -   Stem strength.—Strong.        -   Stem color.—New growth; 144B in color, very sparsely covered            with lenticels 1 mm in length and 0.5 mm in width, 1 per 3            sq cm, and 200A in color; mature bark; 164D.        -   Stem size.—Average of 23 cm (to base of inflorescence) in            length and average of 7 mm in width.        -   Stem surface.—Glabrous, moderately glossy, mature bark;            moderately ridged.        -   Branching.—Basal branching, an average of 8 basal in a            one-gallon container, no secondary branches without            pinching.        -   Internode length.—Average of 3 cm.-   Foliage description:    -   -   Leaf shape.—Broadly elliptic.        -   Leaf arrangement.—Opposite.        -   Leaf division.—Simple.        -   Leaf number.—Average of 12 (6 pairs) per lateral branch.        -   Leaf base.—Cuneate, sometimes oblique.        -   Leaf apex.—Acuminate.        -   Leaf margins.—Serrated.        -   Leaf venation.—Pinnate, conspicuous, color upper surface            145B to 145C, color lower surface 145C.        -   Leaf size.—Average of 13 cm in length and 8 cm in width when            mature.        -   Leaf attachment.—Petiolate.        -   Leaf surface.—Smooth with slight sheen on upper and lower            surface.        -   Leaf color.—Young foliage upper surface; blend of 144A and            137C, young foliage lower surface; blend of 144A and 144B,            mature foliage upper surface; N137A, mature foliage lower            surface; 138B.        -   Petioles.—Average of 1.5 cm in length and 3.5 mm in width,            144B in color, surface is smooth and slightly glossy.-   Inflorescence description:    -   -   Inflorescence type.—Terminal flattened-globular compound            corymb of rotate-shaped showy fertile flowers and less            numerous smaller non-showy fertile flowers held below showy            flowers.        -   Lastingness of inflorescence.—Persistent with color lasting            about 4 weeks.        -   Inflorescence number.—One per lateral or sublateral stem.        -   Inflorescence size.—Average of 9 cm in height and 6 cm in            diameter.        -   Flower number.—An average of 45 showy flowers per            inflorescence and 10 non showy fertile flowers per            inflorescence.        -   Flower fragrance.—None.        -   Flower aspect.—Upright and outward.        -   Flower size.—Showy flowers; an average of 3 cm in diameter            and 1 cm in depth, non-showy flowers; an average of 5 mm in            length and 3.5 mm in width.        -   Flower buds.—Showy flowers; an average of 4 mm in length and            3 mm in width, ovate in shape, 144A in color, non-showy            flowers; an average of 2 mm in length and 1 mm in width,            ovate in shape, 144C in color.        -   Peduncles.—Primary; an average of 1 cm in length and 4 mm in            width, vertical, strong, 144B in color, glabrous surface,            secondary on corymb; an average of 7 mm in length and 1.5 mm            in width, 161B n color with markings of 59A, glabrous            surface.        -   Pedicels.—Showy flowers; an average of 1.7 cm in length and            1 mm in width, held at an average angle of 45° to peduncle,            blend of 63B and 63C in color, strong, glabrous surface,            non-showy flowers; an average of 2 mm in length and 1 mm in            width, held at an average angle of 45° to peduncle, 63C in            color, stout, glabrous surface.        -   Petals.—(Both flower types); 4 mm in diameter and 2 mm in            width, color 63B on upper surface and 63C on lower surface,            broadly acute apex, truncate base, entire margins, glabrous            on upper and lower surface.        -   Sepals.—(Showy flowers); Average of 4, rotate in            arrangement, glabrous and dull surface (both surfaces),            ovate in shape, margin is entire, broadly acute apex,            broadly cuneate to rounded base, an average of 1.5 cm in            length and 1.5 cm in width, color when opening upper and            lower surface; a blend of 144C and 144D, color when fully            open upper surface; a blend of 144B to 144C with markings of            63C and 59B to 59D, color when fully open lower surface;            144B to 144C with markings of 59B to 59C radiating from base            and a thin margin of 59A, color when fully mature upper            surface; a blend of 59A to 59C with blotchy markings of 144A            near apex, color when fully mature lower surface; a blend of            63B to 63D blended with areas of 143D (most towards apex),            non showy flowers; campanulate in shape, fused with            4-starred apex, calyx is 3 mm in length and 2 mm in width,            145C in color with apex margins 145B (inner and outer            surfaces), glabrous surface.-   Reproductive organs: (Showy and non-showy flowers)    -   -   Stamens.—Average of 8, anther is oblong in shape, 1 mm in            length and 157C in color, filament is 4 mm in length and 63C            in color, pollen is moderate in quantity and 144D in color.        -   Pistils.—3, club-shaped, average of 2 mm in length and 1 mm            in width, stigma is 0.5 mm in height, rounded and 157C in            color, style is an average of 1.5 mm in length and 63C in            color, ovary is 145B in color.        -   Fruit and seed.—Has not been observed under the conditions            tested to date.

It is claimed:
 1. A new and distinct cultivar of Hydrangea plant named‘HORWACK’ substantially as herein illustrated and described.